Conventionally, there is known a road condition management system for acquiring information concerning a road condition in a vehicle and managing the road condition information. The system includes an on-board device provided in the vehicle in order to acquire information concerning a road condition and an information server that manages the information concerning the road condition. The on-board device includes a camera for photographing a road condition and a recognition device that applies image recognition to a photographed image obtained by the camera and detects a road condition. The information server collects the information concerning the road condition detected in the vehicle and manages the information.
By using such a road condition management system, for example, an administrator (a road condition administrator) of a road management agency such as a public peace authority can grasp that abnormality is present in a road condition and take measures such as repairing of the road condition. In this case, the on-board device can be mounted on, for example, a police vehicle.
Such a road condition management system adopts, in order to automate management of a road condition, means for photographing a road condition with the camera in the on-board device and applying image recognition with software of the recognition device. Therefore, in order to improve reliability of road condition information managed in the information server, it is necessary to improve accuracy of the image recognition.
As a system for acquiring an image of a road with the on-board device mounted on a vehicle, applying the image recognition to the image to detect a road condition, and transmitting result information of the image recognition to an information center, there is a system described in Patent Literature 1. In the system, in order to improve reliability of the result of the image recognition, the information center calculates a certainty factor of the image recognition from a difference between the result of the image recognition acquired from the on-board device and results of the image recognition in the same location accumulated in the past.